Write it once. Answer everywhere.
Set up the agent and its documents one time, then connect as many channels as your plan allows.
One agent, one set of documents, one inbox.
Every channel runs the same agent, so an answer on WhatsApp matches the answer on your website.
Signed inbound webhooks, and the 24-hour service window is tracked so you don't message outside it by accident.
On your own site, too.
The widget sits in the corner of any page. A visitor asks, and the answer names the document it came from.